&lt;i&gt;In Situ&lt;/i&gt; Synchrotron X-Ray Topography Observation of Double-Ended Frank-Read Sources in PVT-Grown 4H-SiC Wafers

Yang, Yu; Guo, Jianqiu; Raghothamachar, Balaji; Dudley, Michael; Weit, Swetlana; Danilewsky, A.N.; McNally, Patrick J.; Tanner, Brian R.

doi:10.4028/www.scientific.net/msf.924.172

Cited by 9 publications

(9 citation statements)

References 4 publications

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“…While thermal stress does play an important role in the observed relaxation process it is apparently not the only stress that drives the process. If only thermal stress is present, the dislocations will glide similar to other BPDs as described in (12). However, the fact that dislocations stop gliding at the interface and form interfacial dislocations certainly indicates that the effect of mismatch stress is also involved.…”

Section: Misfit Strainmentioning

confidence: 80%

“…When the dislocation stops gliding in Figure 5(d), its morphology is clearly observed. Detailed analysis of those dislocation motions is reported in another paper (12,13), in which the approximate stress field was simulated based on the measured temperature field during this experiment. The result confirms that the crystal was subject to thermal stress and its resolved value on the basal plane has already reached the critical resolved shear stress to move a dislocation.…”

Section: Thermal-assisted Dislocation Motionmentioning

confidence: 99%

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In-Situ Synchrotron X-Ray Topography Study on the Stress Relaxation Process in 4H-SiC Homoepitaxial Layers

Guo¹,

Ailihumaer²,

Peng³

et al. 2018

ECS Trans.

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During 4H silicon carbide (4H-SiC) homoepitaxy and post-growth processes, the development of stress relaxation has been observed, in which interfacial dislocations (IDs) are formed at the epilayer/substrate interface, relaxing the misfit strain induced by the nitrogen doping concentration difference between the epilayer and substrate. It is widely believed that an interfacial dislocation is created by the glide of a mobile segment of a basal plane dislocation (BPD) in the substrate or epilayer towards the interface, leaving a trailing edge component right at the interface. However, direct observation of such mechanisms has not been made in SiC before. In this work, we present an in situ study of the stress relaxation process, in which a specimen cut from a commercial 4H-SiC homoepitaxial wafer undergoes the stress relaxation process during a high-temperature heat treatment while sequential synchrotron white beam X-ray topographs were recorded simultaneously. Based on the dynamic observation of this process, it can be concluded that thermal stress plays a role in the relaxation process while the increased misfit strain at elevated temperature most likely drives the formation of an interfacial dislocation.

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Section: Misfit Strainmentioning

confidence: 80%

Section: Thermal-assisted Dislocation Motionmentioning

confidence: 99%

In-Situ Synchrotron X-Ray Topography Study on the Stress Relaxation Process in 4H-SiC Homoepitaxial Layers

Guo¹,

Ailihumaer²,

Peng³

et al. 2018

ECS Trans.

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“…The yield stress curve can be described as two separate plots of the Eq. [2] with different dependence factor of Q. Before 𝑇 , the thermal energy can only activate the leading Sicore partials which has the lower glide activation enthalpy 𝑄 𝑖 / .…”

Section: Discussionmentioning

confidence: 99%

“…The high brightness of third generation synchrotron radiation sources along with advances in high resolution two-dimensional detector technology render this feasible. Recently, we reported on the direct observation of thermal gradient induced motion of BPDs through in-situ synchrotron X-ray topography imaging of PVT-grown 4H-SiC wafers subject to high temperature treatment [2]. The multiplication of BPDs by the operation and interactions of multiple Frank-Read sources leading to formation of complex configurations was observed.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Basal Plane Dislocation Dynamics in PVT-Grown 4H-SiC Crystals during High Temperature Treatment

et al. 2019

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Fundamental understanding of the generation and multiplication of basal plane dislocations (BPDs) in PVT-grown 4H-SiC crystals is critical for design of growth strategies to control their densities during PVT growth of 4H-SiC crystals. Direct observation of thermal gradient induced motion of basal plane dislocations by in-situ synchrotron X-ray topography imaging of PVT-grown 4H-SiC wafers subject to high temperature treatment has provided an opportunity to analyze the movement of dislocations. Dislocations with Burgers vector along the off-cut [11-20] direction were found to be the only dislocations involved in deformation during heat treatment and the segments of dislocations used for velocity measurements were found to be either pure screw comprised of both Si- and C- core partials or 60° dislocations comprised of purely Si cores. Using the kink-diffusion model, the activation energies for dislocation motion have been estimated from the velocity data for each of these dislocation types and found to be 2.21 eV for 60° and 3.28 eV for pure screw segments, respectively. These values are in good agreement with the macroscopic studies of yielding of semiconductor crystals during high temperature compression and indentation experiments. Quantitative expression of the temperature dependent critical resolved shear stress required for dislocation motion has been derived from this analysis.

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“…[96] By replacing the 450 W halogen lamps by 1000 W lamps, the maximum temperature can be increased from 1200 to 1700°C to allow the direct observation of Si and SiC respectively. [97] Figure 4 and quick time Movie S1, Supporting Information show such a high temperature in situ experiment using a (0001) oriented 4H-SiC wafer. The 1120 reflection was chosen, because of a high contrast of the basal plane dislocations.…”

Section: Dislocation Dynamics In Sic and Simentioning

confidence: 99%

X‐Ray Topography—More than Nice Pictures

Danilewsky

2020

Crystal Research and Technology

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X‐ray topography—a well‐known diffraction imaging method—is widely used for the characterization of extended crystal defects like dislocations. Herein, the progress toward the quantification besides the number and nature of dislocations is given. The diffracted images include additional information about tilt and strain, which can be measured in real‐time, thanks to the improved digital detection systems. This allows not only the fast mapping of huge samples like 450 mm diameter Si wafers, the in situ observation of the dislocation, or crack dynamics at high temperatures, but also the stress analysis in electronic devices in operando. In addition to typical white X‐ray beam methods like stacks of section topographs, the monochromatic diffraction laminography allows a 3D representation of the dislocation arrays. The merits and limitations of X‐ray topography are demonstrated by semiconductor materials as an example.

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<i>In Situ</i> Synchrotron X-Ray Topography Observation of Double-Ended Frank-Read Sources in PVT-Grown 4H-SiC Wafers

Cited by 9 publications

References 4 publications

In-Situ Synchrotron X-Ray Topography Study on the Stress Relaxation Process in 4H-SiC Homoepitaxial Layers

In-Situ Synchrotron X-Ray Topography Study on the Stress Relaxation Process in 4H-SiC Homoepitaxial Layers

Analysis of Basal Plane Dislocation Dynamics in PVT-Grown 4H-SiC Crystals during High Temperature Treatment

X‐Ray Topography—More than Nice Pictures

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